Method of making plant pots



April 9 9 R. A. SP-ENGLER ETAL 2,881,680

METHOD OF MAKING PLANT POTS O riginal Filed Dec. 5. 1952 IN VEN T 0R3finuw A. spa-A6452 40-1650 0- Pay/v04 BY Cannes I44 Svmse 4 I ArrveA/Egsp United States Patent i METHOD OF MAKING PLANT POTS Ralph A. Spengler,Cleveland Heights, Ohio, and Alfred O. Reynolds, Indianapolis, andCharles W. Snyder, Lebanon, Ind.; said Reynolds and said Snyderassignors to said Spengler Original application December 5, 1952, SerialNo. 324,384, now Patent No. 2,728,169, dated December 27, 1955. Dividedand this application August 10, 1955, Serial No. 527,572

7 Claims. (Cl. 92-58) This invention relates to a method for the makingof pots used in growing and/or transplanting plants and, moreparticularly, relates to a method for making pots of the type and kindwhich are shown and described in my copending application, Serial No.324,384 filed Dec. 5, 1952, and now Patent 2,728,169 granted Dec. 27,1955. This application is a division of my copending application aboveidentified.

It has heretofore been proposed to form plant pots of organic materialand various materials and modes of constructing such pots have beenproposed, but the results have not been entirely satisfactory.

An object of this invention, therefore, is to provide an improved methodof making plant pots wherein the pot is formed substantially of organicfibers in such a manner that it is sufficiently sturdy to withstandnormal commercial handling and shipping.

Another object of the invention provides a method of making an improvedplant pot such that the pot has an integral bottom and side wall ofintermeshed organic fibers thereby increasing the strength of the potwhile preserving high porosity, high moisture retention and freedom forroot penetration, the rim of the pot being additionally reenforced toprevent breakage when grasped by the user.

A further object of the invention is to provide an improved method ofmaking plant pots whereby the pot has an integral bottom and side wallsspun from intermingled organic fibers in a manner such that the fibersinterlock and tend to extend generally circularly relative to thevertical center line of the pot, the pot also having 2,881,680 PatentedApr. 14, 1959 Fig. 2 is a top plan view of the pot shown in Fig. l andfurther illustrating, to a somewhat exaggerated de= gree, theorientation of the fibers therein; v

Fig. 3 is a schematic illustration of apparatus which may be utilized inpracticing the method of manufactur= ing pots, examples of such potsbeing shown in Figs. 1 and 2, the said view being partly in sideelevation and partly in vertical section; and a Fig. 4 is a view similarto Fig. 1 but showing a modi= fied form of transplanting pot which maybe made by the method disclosed in the present invention.

In accordance with this invention, the novel plant pots are formed by acircular spinning operation effected upon a liquid suspension or slurryof organic fibers as it is introduced into a perforate mold so that thesaid fibers are interengaged or intermeshed with the bottom of the potbeing integral with the side wall thereof and with the longer fiberstending to be oriented to extend generally circularly relative to thevertical center line of the pot. The liquid suspension or slurry ispreferably formed principally from peat moss which has been subjected tothe action of a wet attrition mill or heater in the presence of water sothat the fibers are thoroughly separated and suspended in the water. Theconsistency of the slurry or suspension, when introduced into the icemold, is preferably in the order of 98% water and 2% an integralreenforcing band adjacent the rim thereof to prevent crumbling orbreakage thereof during handling.

A still further object of the invention is to provide a method of makingplant pots wherein the pot is formed of interlocking peat moss fibers,and provided with a reenforcing band of other cellulose fibers in theregion method of making plant pots whereby the bottom and side wall ofthe pot are integrally formed of peat moss fibers 'spun from a liquidsuspension thereof in a manner such that the principal fibers interlockand tend to extend generally circumferentially of the pot, the outersurface of the-rim portion of the pot being provided with a reenforcingband of other spun cellulose fibers interlocked wth "the fibers in theside wall of the pot.

Other and further objects of the invention will be apparent to thoseskilled in the art to which it pertains from the following descriptionof the present preferred embodiment, and certain modifications thereof,described ,with reference to the accompanying drawing in which:

Fig. 1 is a view principally in side elevation but with 1 a portionbroken away to show a section of a plant pot which is made in accordancewith the method described V ,herein solids, although it will be apparentthat this ratio is not critical. A plant pot formed in this manner, thedetails of which will be hereinafter more fully described, preferablyhas the excess water removed therefrom, while the pot is-still in themold, and the pot is further dried subsequent to removal from the moldby any suitable means.

The completed pot may be employed in the same manner that a clay pot isutilized for the reception of seed or of a transplanted plant and theplant may be watered while thus contained without the need of specialcare or attention to the pot. This is due to the fact that the pot doesnot disintegrate simply under the presence of moisture since the fiberswere thoroughly interengaged or intermeshed by the spinning operation.Nevertheless, the pot is porous and freely permits the penetration ofplant roots therethrough so that the pot may be placed in the groundwithout removal of the plant therefrom.

When this is done, the roots of the plant continue to grow through thepot without appreciable constriction or hindrance while the potgradually disintegrates and adds its substance to the soil. Plant growthmay be stimulated both before and for a time after the pot is placed inthe ground by the addition of various ingredients such as fertilizers,insecticides, or the like, to the body of the pot. This may be'eifected:by mixing such addi- -tives with the organic fibers, such as the peatmoss fibers, either during or subsequent to the milling or beatingoperation; by dipping the completed pots in a solution or solutions ofsuch additives; by spraying the pots with such solutions; or byemploying other known procedures.

Plant pots composed of fibers, such as peat moss :or

combinations thereof with other fibers, and formed by the aforementionedspinning operation, are materially stronger than pots prepared bypressing, molding, or

similar operations since the spinning causes the fibers to .intermesh orinterlock rather than simply layering or stratifying as occurs when thepots are formed by pressing or the like. Consequently, the spun fiberpots can better withstand ordinary commercial handling. It has, however,

been found that any plant pot is subjected to greater stresses in therim portion thereof than in the other parts since the workers engaged intransplanting plants to pots or otherwise handling plant pots on acommercial scale work with considerable speed and customarily grasp thepots adjacent'the rim in'a manner such that forces are exerted whichtend to crush or crumble a portion of the rim. This mode of handling thepots results in considerable breakage and other damage of conventionalorganic pots especially when the pots are moist when handled. One way ofovercoming this defect is to provide a thickened portion of the potadjacent the rim which may be readily effected by providing a suitablyshaped mold. However, in accordance with this invention, still greaterstrength is achieved at this critical location by providing the potswith a reenforcing band about the upper outer surface thereof which bandis preferably formed of a higher strength fibrous material integrallyunited with the fibers of the side wall of the pot.

Referring now to Figs. 1 and 2 of the drawing, the plant pot showntherein is made in accordance with the method as disclosed herein sothat it has a bottom 11 and integral side wall 12 formed of organicfibers, preferably peat moss, which are intermeshed or interlocked withthe longer fibers having a general tendency to be disposedcircumferentially, that is, circularly, relative to the vertical centerline of the pot, as is illustrated to an exaggerated degree in Fig. 2.The upper portion of the side wall 12, adjacent the rim, is thickenedorenlarged and is provided with a reenforcing band 13 of fibers whichare supplied during the initial formation of the pot in a manner suchthat they are subjected to rotary motion so that they intermesh witheach other and with the adjacent fibers of the side wall 12 therebyproviding 'one unitary structure.

The fibers forming the reenforcing band 13 may be either organic orinorganic, but preferably are such that, when disposed as justmentioned, they provide a greater strength per unit dimension than dothe adjacent organic fibers in the main body of the pot. As an exampleof fibers suitable for this purpose, but without limitation thereto, maybe mentioned various cellulose materials of which kraft or newsprintpulps, and especially theformer, have been found particularlyadvantageous. It:is not, however, necessary that the fibers in the band13 be capable of decaying or disintegrating since, being disposedadjacent the top edge of the pot, they will not interfere with the rootgrowth. In fact there are instances where it would be desirable thatthese fibers not disintegrate, since the pot might then be planted inthe ground with the rim portion extending slightly thereabove, thusproviding a protective circle of material about the'stalk of the plantpreventing cut-worms and the like from securing access thereto.

The fibers in the main body of the pot should be principally organicalthough some non-organic fibers may be employed if mingled with theorganic fibers. Peat moss fibers or mixtures thereof with minorquantities of other cellulose fibers, are presently preferred for'themain body of the pot.

A plant pot of'the type disclosed in Figs. 1 and 2 may be'formed byemploying apparatus of various types but for the purposes of thisdisclosure it is sufiicient to note that the method may be performed byan apparatus of thenature schematically illustrated in Fig. 3. Thisapparatus comprisesaperforate mold 14, which may'be formed'of wire' meshor thin sheet metal having suitable spaced openings therethrough andshaped to provide a circular-bottomand tapered side walls, the upperportion of the mold being offset, as indicated at 15, to providethe'thickened band or rim of the completed pot. The

perforate mold 14 is removably supported upon a rotating "means,"generally designated 16, which is shown as comprising a rotatable plateor driving member 17 having suitable drain openings 18 and attachedto-a-- shaft 19 for rotation therewith. The supporting and drivingmember 17 ispreferably positioned within a housing 20 having a drain 21and also provided'with a bearing 22 for'the shaft 19,only a portion'ofthe housing being here illustrated. Beyond the bearing 22, exteriorly ofthe housing 20, the shaft 19 is provided with a means for impartingrotation thereto, which means is here shown as a pulley 23 having adrive belt 24 trained thereabout and driven by a source of power, notshown.

It will be evident from the apparatus thus far described that, when themold 14 is placed upon the supporting member 17 and the latter isrotated by the pulley and belt 23, 24, the mold will be correspondinglyrotated. If desired, one or more complementary projections and recessesmay be provided upon the mold 14 and member 17 to facilitate thetransmission of rotary motion to the mold. In place of the plurality ofsmall openings, the member 17 may simply have a single large opening inwhich the lower portion of the mold 14 is received.

The material for forming the rim and body of the pot are sequentiallysupplied under pressure through separate flexible conduits or hoses 25and 26 communicating, respectively, with tubular members 27 and 28. Themembers 27 and 28 extend radially from an annular member 29 which issupported .upon a shaft 30 for rocking about a horizontal axis in amanner such that either the member -27 or the member 28 may be rocked toa position coaxial with the mold 14. The shaft 35), and hence the partssupported thereon, may be raised and lowered by means not shown.

The outer end of the member 27 is provided with a nozzle member 31having a lateral opening or openings 32 for discharge of the liquidsuspension or slurry supplied through the conduit or hose 25. The nozzlemember 31 has a shaft-like depending portion 33 on wh1ch'a shieldsupporting member 34 is rotatably mounted. The member 34 has a flangeportion 35, adjacent its upper end, which is undercut to receive theinner edge of .a frusto-conicalresilient shield member 36, the latterbeing held in place by a ring 37 which is mounted on'the member 34 andhas a beveled surface engaging the underside of the shield member 36.The member 34 is provided, adjacent its lower end, with radiallyextending pins or screws 38 which are received in longitudinallyextending slots 39 of a shield operating member 40 that is axiallyslidable on the member 34 and is rotatable therewith. Thelower end ofthe member 40 is provided with a foot portion 41 which is adapted toengage the bottom of the mold 14 when the assembly is lowered into themold thereby moving the member 40 upwardly to the position shown in Fig.3 so that the outer edge of the shield member 36 is deflected intoengagement with the mold 14 adjacent the lower edgeof the offset portion15. It will be apparent, therefore that the slurry or liquid suspensionsupplied through the conduit25 issues from the opening or openings 32and is deposited as a band or rim of intermeshed fibers in the offsetportion 15 of the mold. This material is prevented from being thrownfrom the top of the-mold by a cover member 42 which preferably contactsthe top of the mold and is rotatably supported on the nozzle member 31.If desired, the nozzle member 31 may be provided with scraping means toengage the-inner surface of the pot rim as it is formed.

The .tubularmember 28 is provided'on its outer end with an elongatednozzle member 43 having one or more axially elongatedradial openings 44communicating with the conduit 26 through the member 28. The member 43is adapted to'be inserted in the mold 14 by raising the shaft 30 toremove the nozzle member 31 and its shield assembly from the mold andthen rocking thevapparatus about the shaft 30 through an angle ofsubstantially degrees so that the nozzle member 43 is disposedvertically downwardly after which the shaft 30 is lowered to dispose thenozzle member 43 within the mold. When the nozzle member 43 is thuspositioned withinthemold 14 the material supplied through conduit 26issuesfrom seemedwith. If desired, the nozzlemernber 43 may be providedwith scraping means to en'gagej the inner surface of the pot and assistin shaping the latter as it is formed. A cover member 45 is preferablyrotatably supported on the tubular member 28 above the nozzle member 43for cooperation with the upper edge of the mold 14 to prevent thefibrous material from being thrown therefrom.

' In forming a plant pot of the type shown in Figs. 1 and 2, a moldhaving the desired shape, for example, a mold such as 14, is positionedupon the member 17 and the distributing nozzle 31 with its shieldassembly are introduced into the mold 14 with the shield or cover member42 engaging the top of the mold. This introduction of the nozzle andshield member is rendered possible since at this time the shieldoperating member 40 is at its lowermost position on the member 34, dueto the action of gravity which may be assisted by a spring, not shown,with the result that the outer edge of the shield member 36 is permittedto assume its undeflected frustoconical shape. When, however, the footportion 41 engages the bottom of the mold, and the nozzle member islowered to the position shown in Fig. 3, the member 40 deflects theshield member into engagement with the mold adjacent the lower edge ofthe offset portion 15. The driving means is then placed in operation sothat the member 17 and the mold-14 are rotated, whereupon the liquidsuspension of fibrous material, which is to be employed in forming thereenforcing band 13, is supplied to the conduit 25 under sufiicientpressure to flow from the opening or openings 32 into engagement withthe upper portion 15 of the mold 14. Preferably, rotation of the mold iscontinued after supplying of the fibrous material is terminated, thespeed of rotation being such that excess water is thrown off and thefibers are intermeshed with the longer fibers tending to becircumferentially disposed about the inner periphery of offset portion15 of the mold 14. Suflicient material is supplied during this operationto form a band 13 of a thickness such that the. inner surface thereof iseither substantially a continuation of the inner surface of the sidewall of the mold, below the enlarged portion 15, or extends inwardlysomewhat therebeyond.

The apparatus is then elevated sufiiciently to permit rocking of thenozzle members so that the member 43 is now aligned with the mold 14,and the apparatus is again lowered until the cover member 45 engages theupper edge of the mold. The mold is then rotated while a slurry oforganic fibrous material, for example, a slurry of peat moss, issupplied through the conduit 26 and emerges through the openings 44.When sufficient peat moss or other suspended fibers have been introducedto provide a pot of the desired thickness, the supply of the fibroussuspension is terminated, and at least a part of the excess water in thefibers of the pot being formed is removed by more rapidly spinning themold, as explained above. As a result of these operations the fibers ofthe peat moss are circumferentially disposed about the interior of themold 14 both at the bottom and sides thereof and also extending upwardlyto the top of the mold over the inner surface of the band 13.Consequently, the adjacent fibers of the band 13 and of the side wall ofthe pot interengage or intermesh so as to interlock and form an integralunion. Additional water may be removed from the newly formed pot byexerting pressure on the interior thereof, or by other suitable means.After the excess water has been expelled from the material comprisingthe pot within the mold 14, rotation of the mold is terminated and thenozzle 43 is removed therefrom whereupon the pot is removed, suitablydried and is then ready for use.

A plant pot of somewhat different configuration, but formed inaccordance with the principles of this invention, is illustrated in Fig.4. This form of pot has the side wall 46 thereof of uniform taper fromthe circular bottom 47 to the upper or rim portion 48 without the saidrim portion being thickened or enlarged. This pot,

however, is likewiseformed from a liquid suspension 6 slurry ofintermeshed organic fibers introduced into, a perforate mold while it isrotated so that the longer fiberstend to be distributed in a circulardirection extending. about the vertical center line of the pot, theupper or rim portion of the side wall being reenforced by a band 49 ofspun fibers which maybe either organic or inorganic and which areintegrally united with the fibersofv the side wall 46 in the rim portion48. As in the preferred embodiment, the fibers comprising the main bodyof the pot are preferably peat moss, or mixture of peat moss and otherfibers, which has been milled or beaten in Water so that the fibers aregenerally individually separated but not broken. The reenforcing band 49is preferably formed of fibers other than peat moss and which, by way ofexample, may be stated to preferably comprise kraft paper pulp.

The method of forming the pot shown in Fig. 4 is substantially the sameas that employed in constructing the pot shown in Figs. 1 and 2 and maybe effected withan apparatus similar to that shown in Fig. 3 bysubstituting for the mold 14 a similar mold but having a configura tioncomplementary to that of the desired pot. Hence, the steps of the methodutilized in forming the pot shown in Fig. 4 need not be separatelydescribed. Pots of other configurations, with or without holes in thebottoms, or.

even, entirely without bottoms, may likewise be formed in a similarmanner.

When the rcenforcing rim 13 is formed of kraft paper fibers greaterstrength can be provided, especially when the pot is wet, byincorporating one of the substances employed to increase the wetstrength of paper products.

This may be achieved by adding such a substance to thefibers eitherwhile they are being milled or beaten orsubsequent thereto so that thesaid substance treats the: By way of example, synthetic resins,. such asphenol-formaldehyde, urea-formaldehyde, mela-- mine-formaldehyde, or thelike may be so employed in;

individual fibers.

the manner and quantities which will be readily under-- stood by thoseskilled inthe art of paper making. It is: also frequently desirable toincorporate an anti-mildew agent in the fibers used for the rim 13especially where. these fibers are derived from kraft paper scraps thatmay contain sizing or the like. One suitable material for this purposeis zinc dimethyldithiocarbamate in quantities of from 0.1 of 1% to 2% ofthe dry Weight of the fibers depending upon the analysis of thecommercially available form of this substance and whether or not awetting agent is utilized therein.

The main body of the pots may be formed from peat moss fibersexclusively or from mixtures thereof with other cellulose fibers withthe peat moss fibers preferably predominating. For example, newsprintpulp fibers, kraft .paper fibers or combinations thereof may be employed'and maybe treated to increase wet strength and/ or pre-- vent mildew asexplained above for the fibers comprising the reenforcing band. Alsominor quantities of other materials may be incorporated in the pots tofacilitate growth of the plants, to control acidity and/ or to controlinsects.

It will now be evident that, in accordance with this invention, there isprovided an improved plant pot formed principally of organic fibers,which are spun from a liquid suspension in a manner such that the fibersare intermeshed and at least the longer fibers tend to be oriented in agenerally circular configuration. Pots thus constructed havesatisfactory porosity yet possess strength greatly superior to that ofpots which have been pressed from fibers heterogeneously disposed.Moreover, the pots of this invention require no binder in the bodythereof in order to retain their shapes and withstand normal commercialhandling. Furthermore, the rims of the pots are reenforced so that theyare not easily broken during handling even when wet and hence may behandied in the same manner as clay or paper pots. In addition, thereenforcing band cannot be readily detached or loosened from the pot,since it is integrally spun with the material of the pot proper.Furthermore, the novel method of forming the pots facilitates theproduction thereof in commercially significant quantities therebyenabling-the pots to be competitive with other transplanting pots.

While the invention has been disclosed in considerable detail withreference to the preferred embodiment and a modification of theinvention, it will be understood that this detailed description andillustration are intended only by way of example and that variousmodifications and adaptations may be made in the form of the pots andvthe method of their manufacture without departing from the principles ofthe invention. Moreover, while the pots are preferably formedprincipally of peat moss fibers with the reenforcing rim comprisingother cellulose fibers, equivalent materials may be employed and variousadditives utilized as will be evident to those skilled in the art.Consequently, the invention is not to be considered limited except asrequired by the scope of the appended claims.

Having thus described our invention, we claim:

1. The method of forming a plant pot comprising introducing a liquidsuspension of a fibrous material into a perforate mold at only theportion thereof corresponding to the rim of the completed pot whileeifecting relative rotation between said mold and the means forintroducing the suspension, and then introducing a liquid suspension oforganic fibrous material into all parts of said mold while againeffecting the said relative rotation thereby forming a pot ofintermeshed organic fibers with a spun reenforcing band of the firstmentioned fibrous material adjacent the top of the pot and integral withthe side wall of the pot.

2. The method as defined in claim 1 and wherein the first-mentionedfibrous material consists principally of kraft paper fibers and the saidorganic material is principally peat moss.

3. The method as defined in claim 1 and further comprising the removalof excess moisture from the pot While it remains in the mold.

4. The method of forming a plant pot comprising introducing a firstliquid suspension of a fibrous material into a perforate mold adjacentonly the portion thereof corresponding to the rim of the completed potwhile efiecting rotation of said mold relative to the means forintroducing the suspension, terminating introduction of the first liquidsuspension after a band of predetermined thickness has been deposited insaid mold, then introducing a second liquid suspension of diflerentfibrous material into all parts of said mold while again effecting thesaid rotation of the mold relative to the means for introducing thesuspension, and removing the excess water from the deposited fibersthereby forming a pot of intermeshed fibers with the fibers adjacent theupper edge of the pot being difierent from but interengaged with thosein the main body of the pot.

5. The method as defined in claim 4 wherein the firstmentioned liquidsuspension consists principally of kraft paper fibers to which asubstance imparting wet-strength to the fibers has been added.

6. The method of forming a plant pot comprising introducing a firstliquid suspension of a fibrous material into a perforate mold adjacentonly the portion thereof corresponding to the rim of the completed pot,rotating said mold at a speed sufiicient to throw off at least a part ofthe liquid from the deposited fibers, next introducing a second liquidsuspension of difierent fibrous material into all parts of the mold, andthen rapidly rotating said.

mold to throw off at least a part of the liquid from the depositedfibers and thereby provide a pot of intermeshed fibers with the fibersadjacent the upper edge of the pot being different from but interengagedwith those in the main body of the pot.

7. The method of forming a plant pot comprising introducing a firstliquid suspension of a fibrous material into a perforate mold adjacentonly the portion thereof corresponding to the rim of the completed potwhile effecting relative rotation between said mold and the means forintroducing the suspension, terminating introduction of said liquidsuspension after. a quantity thereof sufficient to form a band ofpredetermined thickness has been deposited in the mold, rotating themold at a speed sufficient to throw off at least a part of the liquidfrom the deposited fibers, introducing a second liquid suspension ofdifierent fibrous material into all parts of said mold while againeffecting the said relative rotation between the mold and the means forintroducing the suspension, and again rotating said mold at a speedsufiicient to throw off at least a part of the liquid from the depositedfibers thereby providing a pot of intermeshed fibers with the fibersadjacent the upper edge of the pot being diiferent from but interengagedwith those in the main body of the pot.

References Cited in the file of this patent UNITED STATES PATENTS1,267,632 Claussen May 28, 1918 1,303,191 Fulcher May 6, 1919 1,328,267Cowan Jan. 20, 1920 1,956,776 Simpson May 1, 1934 2,067,716 Landow Ian.12, 1937 2,526,125 Francis Oct. 17, 1950 2,685,969 Curtis Aug. 10, 19542,728,169 Spenger et a1. Dec. 27, 1955 FOREIGN PATENTS 641,280 GreatBritain Aug. 9, 1950

